One-way valve

ABSTRACT

A one-way valve comprising flat resilient members in face-to-face relationship which are bonded upon two generally parallel tracks defining a passageway therebetween, where the tracks have a tortuous profile along their inner edges.

This is a continuation of co-pending application Ser. No. 07/097,171 ,now abandoned filed on 9-16-87.

BACKGROUND OF THE INVENTION

This invention relates generally to one-way valves. More particularly,this invention relates to improve one-way valves constructed from flatresilient members bonded in face-to-face relationship.

The term "one-way valve" is intended to mean a device which allows thepassage of substances through it in one direction only. Such valves areused in a host of applications, including medical applications, wherefluids must be withdrawn from body cavities without reflux to thecavities.

It is most desirable to be able to achieve low "crack" resistance inone-way valves, so that the valves will open in the desired direction offlow on the application of minimal pressure. Similarly, it is mostdesirable to maximize reflux sensitivity of such valves, so that theywill close quickly to prevent back-flow through the valve. It islikewise important that the valves continue to operate when particulatematter becomes lodged in the valves.

In many applications requiring one-way valves, it is important that thevalves be compact and flexible, so that they do not occupy excessivespace in the devices in which they are employed.

Finally, it is often important that the valves have a long shelf like,so that they will be reliable whenever the devices in which theyemployed are put to use. In addition, for medical applications, thevalves must be constructed from materials approved for use in thetreatment of human subjects.

SUMMARY OF THE INVENTION

It is therefore one important object of the present invention to providea highly sensitive one-way valve which has low crack resistance and highreflux sensitivity.

It is a further object of the present invention to provide a one-wayvalve which continues to function when particulate matter becomes lodgedin its passageway.

It is another object of the present invention to provide a one-way valvewhich occupies minimum space in the devices in which it is employed.

Yet another object of the present invention is to provide a one-wayvalve which is particularly well suited to applications in medicalapparatus, by virtue of its construction from materials approved for usein medical applications.

Finally, it is yet a further object of the present invention to providea one-way valve which is structurally simple, readily fabricated andhighly reliable over extended periods of time.

These and other objects of the present invention will be apparent fromthe discussion below.

The present invention is therefore directed to a one-way valvecomprising two flat resilient members in face-to-face relationship witheach other. The resilient members are bonded along two generallyparallel tracks which define a passageway therebetween. The tracks havea tortuous profile along their inner edges. Finally, inlet and outletports are provided at the opposing ends of the passageway.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of this invention which are believed to be novel are setforth with particularity in the appended claims. The invention, togetherwith its objects and advantages thereof, may be best understood byreference to the following description taken in conjunction with theaccompanying drawings, in which like reference numerals identify likeelements in the several figures and in which:

FIG. 1 is a plan view of a one-way valve constructed in accordance withthe present invention;

FIG. 2 is a cross-sectional view of the valve of FIG. 1, taken alonglines 2--2 thereof;

FIG. 3 is a cross-sectional view of the valve of FIG. 1, taken alonglines 3--3 thereof;

FIG. 4 is a plan view of the valve of FIG. 1 illustrating flow of fluidtherethrough;

FIG. 5 is a cross-sectional view of the valve of FIG. 4, taken alonglines 5--5 thereof;

FIG. 6 is a plan view of a one-way valve lacking the tortuous passagewayprofile of the present invention;

FIG. 7 is a cross-sectional view of the valve of FIG. 6, taken alonglines 7--7 thereof; and

FIG. 8 is a plan view of a one-way valve having two independentpassageways.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to FIGS. 1-3, a one-way valve 10 is illustrated, includingflat resilient members 12 and 14 in face-to-face relationship with eachother. Flat resilient members 12 and 14 are bonded along generallyparallel tracks 16 and 18 which define a passageway 20 therebetweenwhich, as shown in FIGS. 1 and 4, is of the same width at its proximaland distal ends.

Tracks 16 and 18 come together near the top of the valve 19 to define aninlet port 22 which is narrower than passageway 20. Inlet port 22 issealingly attached to a rigid conduit 24. Valve 10 is also provided withan outlet port 25 at the opposide end of passageway 20.

Tracks 16 and 18 each have a tortuous profile along their respectiveinner edges 26 and 28. In the embodiment illustrated, the tortuousprofile comprises a series of sawteeth 30 projecting from each of thetrack inner edges into passageway 20. Each sawtooth has a leading edge32 and a trailing edge 34. The sawteeth are positioned with theirleading edges oriented toward the outlet port and their trailing edgesoriented towards the inlet port.

The tortuous profile may take various different forms which createtwists, turns, curves and windings along the outer edges of passageway20 to prevent reflux flow along the outer edges of the valve passageway,as explained below.

When a suction force is applied to conduit 24, as indicated by the arrow36, the valve takes on the respective cross-sectional profilesillustrated in FIGS. 2 and 3. Thus, any fluid 38, which is drawn upalong the initial generally straight edges of passageway 20 at outletport 25 (FIG. 3) will not pass through the valve, as explained below inconnection with the discussion regarding FIGS. 6 and 7.

Resilient members 12 and 14 may be made from a wide variety of resilientmaterials including for example, polyethylene, mylar, nylon andpolyvinyl chloride. All of these materials are approved for use in thetreatment of human subjects. The resilient members should be from about1 to about 10 mils in thickness, although it is preferred that theresilient members be from about 3 to about 5 mils thick. In aparticularly preferred embodiment, the resilient members will be about 3mils in thickness.

The resilient members may be bonded to each other and to rigid conduit24 by any conventionally available means which would not unduly restrictthe operation of the valve. It is preferred that the resilient layers bebonded by a heat sealing technique such as thermal impulse heating orhot bar heating. Among presently available bonding techniques, thermalimpulse heating has been found to be particularly desirable. Thetemperatures, pressures and other parameters used in bonding theresilient members will depend upon the material of the resilientmembers, their thickness, the length and width of the valve, and thedesired valve crack resistance and reflux sensitivity.

In one preferred embodiment in which a heat-sealing bonding method isused, the resilient members are laminates comprising a heat-sealablelayer and a thermally-resistant layer. In this embodiment, thethermally-resistant layer primarily governs the physical properties ofthe valve while the heat-sealable layer bonds the resilient members.These laminated resilient members are disposed in the valve with theirheat-sealable layers in face-to-face relationship. Thus, theheat-sealable layers will melt and adhere during the bonding process ata bonding temperature which will not significantly alter the resilience,integrity, and other necessary and desirable characteristics of thethermally-resistant layer.

The laminated resilient layers may be made by any known means, includingconventional lamination and coextrusion techniques. Also, where alaminated material is used, the heat-sealable layer should be from about2.5 to about 3.5 mils in thickness and the thermally-resistant layershould be from about 0.50 to about 0.75 mils in thickness. In aparticularly preferred embodiment, the heat-sealable layer should beabout 3.0 mils in thickness and the thermally-resistant layer should beabout 0.75 mils in thickness.

The heat-sealable layer of the laminated resilient members may be chosenfrom the group consisting of low density polyethylene and ethyl vinylacetate. The thermally-resistant layer may be chosen from the groupconsisting of nylon, mylar and linear low density polyethylene. Aparticularly preferred laminated material, comprising low densitypolyethylene and nylon, can be made by laminating low densitypolyethylene to Capran film available from Allied Engineered Plastics ofMooristown, N.J.. This laminated material takes on certain desirablecharacteristics of the nylon including outstanding resistance topuncture, abrasion and flex cracking, as well as high burst and impactstrength and high tensile and tear strength.

Although the valve illustrated in FIG. 1 shows a single pair of tracks16 and 18 and a single passageway 20, as illustrated in FIG. 8, one-wayvalve 21 in accordance with the present invention may have two or morepairs of sealing tracks defining a plurality of passageways 20A, 20B,with the passageways having a single common inlet, 22A, and a pluralityof independent outlet ports, 25A, 25B. In addition, one-way valves inaccordance with the teaching of the present invention may be made invarious lengths and widths to tailor the valve properties to the desiredapplications.

The valve illustrated in FIG. 1 can be used in medical applications, forexample, to drain fluid and gases from the chest, where it is essentialthat the liquids and gases be permitted to escape without reflux. Inthis application, it is important that the valve prevent blood clots andother solids expelled from the chest cavity from causing valve failure.

Thus, rigid conduit 24 would be connected to a drain placed in the chestcavity (not shown). As illustrated in FIG. 4, gases and fluids expelledfrom the chest cavity flow through conduit 24, inlet port 22 andpassageway 20 into a receptacle (not shown) containing liquid 38. When asuction force is applied to the conduit, the valve closes, asillustrated in FIGS. 1-3, to prevent liquids and gases from being drawnback up through the valve and into the chest cavity. Due to the designof the valve, blood clots and other solids which may be introduced intopassageway 20 during the draining procedure are held in place and willnot interfere with the operation of the valve. The opposing faces ofresilient members 16 and 18 simply seal above and below such solidswithout hindering valve function.

While the invention is not intended to be limited by any particulartheory of the operation of valve 10, in the absence of a tortuousprofile, as in the valve 40 illustrated in FIGS. 6 and 7, fluid leakageresults under high suction forces. Apparently, such leakage occurs, dueto the formation of small channels 42 along the inner edges 44 of tracks46 and 48 which permit fluids (liquids or gases) to travel up the valvewhen suction is applied to conduit 50.

The tortuous profile in valve 10 (FIG. 1) interrupts the channels whichotherwise form along the outer edges of the valve passageway,redirecting the flow toward the center of the passageway where it iseffectively blocked. The tortuous profile is also believed to maintainthe opposing faces of resilient members 12 and 14 in enhanced intimatecontact to improve the reflux sensitivity of the valve.

While particular embodiments of the invention have been shown anddescribed, it will be obvious to those skilled in the art that variouschanges and modifications may be made therein without departing from thespirit and scope of the invention and, therefore, it is intended in theappended claims to cover all such changes and modifications which fallwithin the true spirit and scope of the invention.

We claim:
 1. A one-way valve comprising:two flat resilient members inface-to-face relationship with each other, said resilient members beingbonded along two generally parallel tracks defining a passagewaytherebetween, each of said tracks having a tortuous profile along itsinner edge, each of said tortuous profiles converging toward the othermore than once along said passageway; and an inlet port at one end ofsaid passageway and an outlet port at the opposite end of thepassageway.
 2. The one-way valve of claim 1 wherein said resilientmembers are made from a material chosen from the group consisting ofpolyethylene, mylar, nylon and polyvinyl chloride.
 3. The one-way valveof claim 1 wherein each of said resilient members has a heat-sealablelayer and a thermally-resistant layer, said resilient members beingdisposed with their heat-sealable layers in face-to-face relationship.4. The one-way valve of claim 3 wherein said heat-sealable layer ischosen from the group consisting of low density polyethylene and ethylvinyl acetete and the thermally-resistant layer is chosen from the groupconsisting of nylon, mylar, linear low density polyethylene.
 5. Theone-way valve of claim 3 wherein each of said resilient layers is alaminate of low density polyethylene and nylon.
 6. The one-way of claim3 wherein said heat-sealable layer is from about 2.5 to about 3.0 milsin thickness and said thermally-resistant layer is from about 0.50 toabout 0.75 mils in thickness.
 7. The one-way valve of claim 3 whereinsaid heat-sealable layer is about 3.0 mils in thickness and saidthermally-resistant layer is from about 0.75 mils in thickness.
 8. Theone-way valve of claim 3 wherein each of said resilient layers is alaminate of low density polyethene and nylon.
 9. The one-way valve ofclaim 1 wherein each of said resilient members is from about 1 to about10 mils in thickness.
 10. The one-way valve of claim 1 wherein each ofsaid resilient members is from about 3 to about 5 mils in thickness. 11.The one-way valve of claim 1 wherein each of said resilient members isabout 3 mils in thickness.
 12. The one-way valve of claim 1 wherein saidvalve includes greater than two sealing tracks, said sealing tracksdefining a plurality of passageways, said passageways having a commoninlet port and a plurality of independent outlet ports.
 13. The one-wayvalve of claim 1 wherein said tortuous profile comprises a sawtoothpattern.
 14. The one-way valve of claim 13 wherein said sawtooth patterncomprises at least one sawtooth projecting from each of said tracks intosaid passageway.
 15. The one-way valve of claim 14 wherein each saidsawtooth includes a leading edge and a trailing edge, said sawteethbeing oriented with their leading edges directed toward said outlet portand said trailing edges toward said inlet port.
 16. A one-way valvecomprising:two flat resilient members comprising a heat-sealable layerand a thermally-resistant layer in face-to-face relationship with eachother, said resilient members being disposed with their heat-sealablelayers in face-to-face relationship, said resilient members furtherbeing bonded along two generally parallel tracks defining a passagewaytherebetween, said tracks having a tortuous profile along their inneredges; and an inlet port at one end of said passageway and an outletport at the opposite end of said passageway.
 17. The one-way valve ofclaim 16 wherein said heat-sealable layer is chosen from the groupconsisting of low density polyethylene and ethyl vinyl acetate, and thethermally-resistant layer is chosen from the group consisting of nylon,mylar and linear low density polyethylene.
 18. The one-way valve ofclaim 16 wherein said heat-sealable layer is from about 2.5 to about 3.5mils in thickness and said thermally-resistant layer is from about 0.50to about 0.75 mils in thickness.
 19. The one-way valve of claim 16wherein said heat-sealable layer is about 3.0 mils in thickness and saidthermally-resistant layer is from about 0.75 mils in thickness.
 20. Theone-way valve of claim 16 wherein said resilient members are made from amaterial chosen from the group consisting of polyethylene, mylar, nylonand polyvinyl chloride.
 21. The one-way valve of claim 16 wherein saidheat-sealable layer is chosen from the group consisting of low densitypolyethylene and ethyl vinyl acetate and the thermally-resistant layeris chosen from the group consisting of nylon, mylar, and linear lowdensity polyethylene.
 22. The one-way valve of claim 16 wherein each ofsaid resilient layers is a laminate of low density polyethylene andnylon.
 23. The one-way valve of claim 16 wherein said heat-sealablelayer is from about 2.5 to about 3.0 mils in thickness and saidthermally-resistant layer is from about 0.5 to about 0.75 mils inthickness.
 24. The one-way valve of claim 16 wherein said heat-sealablelayer is about 3.0 mils in thickness and said thermally-resistant layeris from about 0.75 mils in thickness.
 25. The one-way valve of claim 16wherein said valve includes greater than two sealing tracks, saidsealing tracks defining a plurality of passageways, said passagewayshaving a common inlet port and a plurality of independent outlet ports.26. The one-way valve of claim 16 wherein said tortuous profilecomprises a sawtooth pattern.
 27. The one-way valve of claim 16 whereinsaid sawtooth pattern comprises at least one sawtooth projecting fromeach of said tracks into said passageway.
 28. The one-way valve of claim27 wherein each said sawtooth includes a leading edge and a trailingedge, said sawteeth being oriented with their leading edges directedtoward said outlet port and said trailing edges toward said inlet port.29. A one-way valve comprising:two flat resilient members comprising aheat-sealable layer and a thermally-resistant layer being disposed withtheir heat-sealable layers in face-to-face relationship, said resilientmembers further being bonded along two tracks defining a passagewaytherebetween, said tracks having a tortuous profile along their inneredges, said tortuous profile comprising at least one sawtooth projectingfrom each of said tracks into said passageway; and an inlet port at oneend of said passageway and an outlet port at the opposite end of saidpassageway.